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authorMike Kravetz2015-09-08 15:01:41 -0700
committerLinus Torvalds2015-09-08 15:35:28 -0700
commitb5cec28d36f5ee6b4e6f68a0a40aa1e4045d6d99 (patch)
tree85ce12770ae20ac0cfdbd63822796c59dc57eea0 /mm/hugetlb.c
parent1bfad99ab42569807d0ca1698449cae5e8c0334a (diff)
hugetlbfs: truncate_hugepages() takes a range of pages
Modify truncate_hugepages() to take a range of pages (start, end) instead of simply start. If an end value of LLONG_MAX is passed, the current "truncate" functionality is maintained. Existing callers are modified to pass LLONG_MAX as end of range. By keying off end == LLONG_MAX, the routine behaves differently for truncate and hole punch. Page removal is now synchronized with page allocation via faults by using the fault mutex table. The hole punch case can experience the rare region_del error and must handle accordingly. Add the routine hugetlb_fix_reserve_counts to fix up reserve counts in the case where region_del returns an error. Since the routine handles more than just the truncate case, it is renamed to remove_inode_hugepages(). To be consistent, the routine truncate_huge_page() is renamed remove_huge_page(). Downstream of remove_inode_hugepages(), the routine hugetlb_unreserve_pages() is also modified to take a range of pages. hugetlb_unreserve_pages is modified to detect an error from region_del and pass it back to the caller. Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c40
1 files changed, 37 insertions, 3 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 070880fe1ff7..61c52cd5f77b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -547,6 +547,28 @@ retry:
}
/*
+ * A rare out of memory error was encountered which prevented removal of
+ * the reserve map region for a page. The huge page itself was free'ed
+ * and removed from the page cache. This routine will adjust the subpool
+ * usage count, and the global reserve count if needed. By incrementing
+ * these counts, the reserve map entry which could not be deleted will
+ * appear as a "reserved" entry instead of simply dangling with incorrect
+ * counts.
+ */
+void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserve)
+{
+ struct hugepage_subpool *spool = subpool_inode(inode);
+ long rsv_adjust;
+
+ rsv_adjust = hugepage_subpool_get_pages(spool, 1);
+ if (restore_reserve && rsv_adjust) {
+ struct hstate *h = hstate_inode(inode);
+
+ hugetlb_acct_memory(h, 1);
+ }
+}
+
+/*
* Count and return the number of huge pages in the reserve map
* that intersect with the range [f, t).
*/
@@ -3909,7 +3931,8 @@ out_err:
return ret;
}
-void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
+long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
+ long freed)
{
struct hstate *h = hstate_inode(inode);
struct resv_map *resv_map = inode_resv_map(inode);
@@ -3917,8 +3940,17 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
struct hugepage_subpool *spool = subpool_inode(inode);
long gbl_reserve;
- if (resv_map)
- chg = region_del(resv_map, offset, LONG_MAX);
+ if (resv_map) {
+ chg = region_del(resv_map, start, end);
+ /*
+ * region_del() can fail in the rare case where a region
+ * must be split and another region descriptor can not be
+ * allocated. If end == LONG_MAX, it will not fail.
+ */
+ if (chg < 0)
+ return chg;
+ }
+
spin_lock(&inode->i_lock);
inode->i_blocks -= (blocks_per_huge_page(h) * freed);
spin_unlock(&inode->i_lock);
@@ -3929,6 +3961,8 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
*/
gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
hugetlb_acct_memory(h, -gbl_reserve);
+
+ return 0;
}
#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE